The present invention relates to a muffled hydrostatic displacement machine.
A muffled hydrostatic displacement machine of this type is known from DE-OS 39 21 790. The core of this hydrostatic displacement machine consists in sealing--based on the displacement ring--the radially outer area relative to the radially inner area in such a way and having such a varying pressure act upon it that the noise level caused by the position of the displacement ring will be reduced.
The known conception, or design, has uniquely proved itself in conjunction with the basic idea--it is somewhat problematic only insofar as relatively close tolerances must be observed so as to avoid, because of the axially one-sided seal, an insufficient or excessive contact force. Insufficient contact pressure leads to a lacking sealing effect; excessive contact pressure entails problems in the adjustment or setting of the displacement ring, particularly with low adjustment pressures. On the end away from the seal, moreover, leakages may occur as well, due to pump housing deformations depending on operating pressure.
The German utility patent 84 07 367 shows displacement elements (FIG. 1, part 17, or FIG. 1, part 16) which, viewed axially, are attached to the displacement ring (14 or 20) by way of two retaining rings (33, 34 or 26, 27).
The German patent publication 24 30 119 shows a radial seal (grooves in the displacement ring) between displacement ring and retaining ring (FIG. 1).
The problem underlying the invention is to provide a hydrostatic displacement machine where, despite close tolerances, the necessary tightness is achievable between the radially outer and radially inner areas.